Relative Consistency in Size, Shape, and Coloration of Savannah Sparrow Eggs within and between Breeding Seasons
Bibliographic record
Abstract
Within bird populations, eggs vary extensively in size, shape, and color, but individual females tend to lay eggs that are relatively consistent in most traits. We measured all eggs laid by individual female Savannah Sparrows (Passerculus sandwichensis) breeding on Kent Island, New Brunswick, comparing subsequent clutches within the same year and in successive years. Repeatability was high for egg size and shape (0.78 and 0.72, respectively). Conversely, the repeatability of intensity of spotting was only moderate (0.46), and the background color of eggs varied from clutch to clutch and even within a clutch. Egg size increased slightly within a year from a female's first to subsequent clutch, but egg size was independent of the female's body size, the age or size of her mate, or weather conditions during clutch formation. Ranking of individual females' eggs by size and shape remained almost the same from clutch to clutch. Although laying eggs that are relatively consistent and individually distinctive in size, shape, and spotting could be an adaptation to allow females to discriminate their own eggs from those of brood parasites, this explanation does not apply on Kent Island, where neither intra- nor interspecific brood parasitism occurs. We found no evidence of short-term effects of egg size on the size of 7-day-old nestlings or of long-term effects on adults' survival or lifetime reproductive success. High repeatabilities suggest a substantial genetic component to variation in certain egg traits, which could limit females' ability to modify their eggs in response to environmental changes.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".